Compositions and processes



Patented Dec. 25, 1945 COMPOSITIONS AND PROCESSES Richard W. Kingerley, Jr., Lakewood Ohio, as-

signor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 5, 1943, Serial No. 478,114

Claims. ((1. 252 434) This invention relates to extreme pressure lubricants and is more particularly directed to E. P. lubricants for the cold reduction of steel which are comprised of a mineral oil and a sulfonated oil.

In the cold reduction of steel strip, it is necessary to use a lubricant on the strip as it passes through the pressure rolls. This is true either of a reversing mill or of a, tandem mill. This lubricant is necessary to prevent the steel from sticking to the pressure rolls, as well as to facllitate its passage through them. The quality of the lubricant determines, to a large extent, the speed at which the mills may operate within their mechanical limitations, and also the flatness. surface appearance and characteristics of the cold rolled sheet coming from the mill.

The lubricant also serves to some extent as a medium for dissipating the heat generated in reducingthe steel. It is general practice, however, to use water in connection with the lubricant as a coolant. In some cases, the water and lubricating oil may be flowed separately on the sheet as it goes to the rolls, and, in other cases, an emulsion of the lubricant in water may be used as a combination lubricant and coolant. It is thus necessary for the lubricant not only to have the requisite film strength properties to perform satisfactorily as a lubricatin agent under these conditions, but also to have the property of spreading quickly and completely over a steel surface in the presence of water.

After the steel strip has passed through the cold reducing rolls, it is general practice to clean the oil and other dirt from it before it passes to the annealing furnaces and other fabricating operations. Usually, this cleaning is performed electrically by passing the strip through a bath containing an alkaline detergent, the strip being made either the cathode, the anode, or a central conductor between alternate cathodes and anodes. The electrocleanlng procedure is used to obtain high speed of operation, usually about equal to the speed of the cold rolling mill, and to insure a. high degree of cleanliness of the strip.

In the past, it has been the practice to use a lubricant consisting either wholly or in part of palm oil. This material has generally been considered satisfactory for this use since it possesses reasonably high film strength values, it spreads readily over a water wetted surface and can be readily removed from the sheet by saponification with a strong alkali. Palm oil has been com blned with ordinary oils and with the so-called soluble oils as lubricants for this purpose. These combinations have been made in an effort to secure a cheaper lubricant and in some instances to secure a better lubricant. However, such compositions have not been too successful in replaclng straight palm oil.

Mineral oil or petroleum oil has been frequently tried as a cold rolling lubricant. In isolated cases, it has proven satisfactory where the speed of the cold reduction mill is quite slow and where the degree of reduction is not unduly large. In general, however, mineral oil has not proven a satisfactory cold rolling lubricant because, among other things, it has been found quite difficult to remove from the strip. Combinations of mineral oil and palm oil have generally shown about the same characteristics as palm oil, providing the mineral oil component is not too large. In these cases, the mineral oil can perhaps be regarded as carriers for the active palm oil.

It is an object of this invention to provide a cold rolling lubricant consisting essentially of mineral oil which will meet the rigid requirements of the present high-speed rolling mills. It is a further object of this invention to provide E. P. lubricants comprised essentially of mineral oil which can readily be removed from steel by electrocleaning in a sodium silicate detergent. It is a still further object to provide compositions which can be added to mineral oil to give it the characteristics of a satisfactory lubricant for the cold rolling of steel. Further objects will become apparent hereinafter.

The foregoing and other objects of the invention are attained by employing an oil-soluble sulfonated animal or vegetable oil in a mineral oil which also includes a compound or compounds which increase its film strength and which increase its spreading characteristics. More speciflcall it is preferred to add a composition comprising sulfonated castor oil, tricresyl phosphate and lorol phosphate, all dissolved in kerosene to a mineral oil to produce an E. P. lubricant satisfactory for the cold reduction of steel.

The mineral oil which comprises the major proportion of an E. P. lubricant composition of the present invention may be any light to heavy mineral oil. In general any mineral oil of a viscosity from 50 to 200 seconds, S. S. U. F), may be used. An ordinary red engine oil, for instance. is satisfactory.

One of the additions to be made to mineral oil to produce lubricants of the present invention is an agent for increasing film strength. It is of course well-known to increase the film strength of mineral oils for E. P. lubricants in various arts and any of the agents useful for this purpose may be employed in compositions of the present invention. There may be used for instance such materials as:

Tricresyl phosphate Dilauryl phosphate Dicyclohexyl phosphate Triphenyl phosphlte Dilauryl trithlophosphite Stearamlde Hexachlorodiphenyloxide Stearonitrile Ethyl oleate Sulfurized sperm oil 'Iriphenyl thiophosphate Tricresyl trithiophosphite 'Iri orthochlorphenyl) tithiophosphate Most of the agents useful for increasing the film strength of mineral oil increase the time required for cleaning the oil from steel surfaces. However it was found that tricresyl phosphate produces the desired increase in film strength without adversely affecting the cleaning time using an electrocleaning process in a sodium silicate detergent bath. It is accordingly preferred to use tricresyl phosphate in the preparation of compositions of the present invention.

An agent for increasing film strength may be used in amounts comparable to those heretofore employed in E. P. lubricants. More specifically it may be indicated that these agents and particularly tricresyl phosphate may be used in an amount equivalent to about 0.5 to 2 percent by weight of the lubricant. More specifically tricresyl phosphate should be used in amount equivalent to from about 1 to 1.5 percent by weight of the lubricant though the precise amount to use in a. particular instance will depend upon the character of the mineral oil and the specific conditions of use.

A material for increasing the spreading characteristics of mineral oil is also included in compositions according to the present invention. The art is already aware of a number of oil-soluble surface active agents that can be used to improve the spreading characteristics of oil in the presence of water. Many of these materials are in themselves also capable of increasing the film strength of an E. P. lubricant.

Typical of the oil-soluble surface active agents for improving the spreading characteristics of oil are mono, di, and tri lorol phosphates and commercial mixtures of them, aryl amine lauryl sulfates, alkyl sulfates such as those shown in Tisdale et al. 2,128,973 and "Tween 81," a sorbitan monooleate polyoxyalkylene derivative.

While as indicated any of the oil-soluble surface active agents known to the art may be employed in compositions according to the present invention most of these materials increase the time required for removing the oil from the steel. A preferred material of the present invention, lorol phosphate, was found however to have very little adverse effect at the concentrations used upon the time required to electroclean steel in a silicate detergent. Lorol phosphate is itself very effective in increasing the film strength of oil but it is used in concentrations below those which would contribute significantly to film strength.

Oil-soluble surface active agents can be used in amounts comparable to those heretofore employed and in general such an agent or preferably lorol phosphate will be used in an amount equivalent to from about 0.05 to 0.3 percent by weight of the total lubricant. More specifically it has been found desirable to use from about 0.1 to 0.2 percent of lorol phosphate.

E. P. lubricant compositions for the cold reduction of steel according to the present invention contain an oil-dispersible sulfonated vegetable or animal oil. Any such sulfonated oil which is oil-soluble may be employed in compositions of the present invention. By "oil-soluble" or "oll-dispersible" I mean to include products soluble, dispersible, or emulsifiable in oil. Typical oi sulfonated oils which may be used are the following:

Sulfonated fish oil Sulfonated lard oil Sulfonated sperm oil Sulfonated soya bean oil Sulfonated peanut oil Sulfonated corn oil Sulfonated cotton seed oil Sulfonated castor oil A suitable sulfonated material for use in compositions of the present invention is sulfonated castor oil. By employing this material in a mineral oil lubricant the time required to electroclean steel in a sodium silicate detergent is reduced to a minimum.

The oil-dispersible sulionated oil may be used in sufficient amount to reduce the cleaning time to the desired extent though of course it will not be practical to use very large amounts. In general it will be found desirable to use from about 0.2 to 0.5 percent of such a material and preferably sulfonated castor oil based on the weight of the mineral oil.

It is a preferred practice of the present invention to prepare a composition including the additions above discussed so that they can be incorporated with the mineral oil in the steel mill as a single addition agent. To this end the addition agents are first dissolved in a mutual solvent and for this purpose kerosene serves very well.

In preparing the composition it is preferable first to add the lorol phosphate followed by the sulionated castor oil and tricresyl phosphate The amount of solvent should be that required to effect solution and with kerosene this will be an amount about equivalent to the quantity of addition agents. Instead of kerosene there may be used any other suitable solvent such as tetralin,

' toluene, and petroleum fractions ranging from light naphthas to kerosene.

As an example of a preferred composition for addition to mineral oil according to the present invention there may be tabulated the following:

Parts by weight Kerosene 20 Tricresyl phosphate 15 Lorol phosphate 1.5 Sulfonated castor oil 3 The composition just shown may be added to mineral oil at concentrations from about 2 to 5 percent by weight. The mineral 011 thus modifled is comparable to palm oil for use in the cold reduction of steel and the lubricant is quickly removed from steel by electrocleaning in a sodium silicate detergent.

Steel strips coated with the modified mineral oil were cleaned electrically by immersing in a detergent solution. In an apparatus in which the solution is flowed past the sheets, the current density was maintained at 35 amps/sq. ft. and

The dethe steel sheet was. made the cathode. tergent was comprised of a sodium silicate solution of 2.0 SiOn/NazO weight ratio at a concentration of 4.7 oz. of solid/gal. and a temperature of 200 F. Under these conditions, acleaning time of about 1 /2 seconds was required to clean mineral oil from the sheet to the point where it was free from water break."

It may be indicated that a preferred silicate detergent will include sodium silicate having asilica to soda weight ratio of 1.9 to 2.4 together with a foaming agent such as a polyethylene oxide derivative or saponin. Compositions for the removal of lubricant films of the present invention are more specifically covered in my pending application, Serial Number 487,115 filed March 5, 1943.

While it will ordinarily be preferred to use mineral oil with only the additions above described it will be understood that various other additions and modifications used in the art may be employed without departing from the spirit of the invention. It may for instance be found desirable to include minor amounts of palm oil or other materials such as soluble oils.

While certain illustrative compositions have been described above it will be understood that the ingredients and the proportions may be considerably varied and regulated to produce lubricants of desired character without departing from the spirit of this invention.

I claim:

1. A lubricant for use in the cold roliing of steel comprising a major amount of mineral oil,

from about 0.2 to 0.5 percent sulfonated castor oil, 0.5 to 2.0 percent tricresyl phosphate, and from about 0.05 to 0.3 percent of lorol phosphate.

2. A composition for addition to mineral oil to produce a. lubricant for use in the cold rollinfl of steel comprising substantially 0.2 to 0.5 percent oi sulionated castor oil, substantially 0.5 to 2.0 percent of tricresyl phosphate, and substantially 0.05 to 0.3 percent of lorol phosphate.

3. A composition for addition to mineral oil to produce a high-pressure lubricant suitable for use in the cold rolling of steel, the lubricant being readily removable from steel by use of a silicate detergent, comprising about 20 parts by weight of kerosene, about 15 parts by weight of tricresyl phosphate, about 1.5 parts by weight of lorol phosphate, and about 3 parts by weight of sulionated castor oil.

4. A lubricant for use in the cold-rolling 01. steel comprising a major amount of mineral oil from about 0.2 to 0.5 percent of a sulfonated 011 selected from the group consisting of sulfonated animal and vegetable oils, 0.5 to 2.0 percent tricresyl phosphate, and from about 0.05 to 0.3 percent of lorol phosphate.

5. A composition for addition to mineral oil to produce a lubricant for use in the cold-rollin of steel comprising substantially 0.2 to 0.5 percent of a sulfonated oil selected from the group consisting of suli'onated animal and vegetable oils. substantially 0.5 to 2.0 percent of tricresyl phosphate, and substantially 0.05 to 0.3 percent of lorol phosphate.

RICHARD W. KINGERIEY, Ja.

CERTIFICATE OF CORRECTION Patent No. 2,591, 651.

December 25, 1915.

RICHARD W. RINGERLEY, JR

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 16, for the serial number '*i 37,115" read --l 7 ,115--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of March, A. D. 1914.6.

(Seal) Leslie Frazer First Assistant Comnisslonpr of Patents.

The dethe steel sheet was. made the cathode. tergent was comprised of a sodium silicate solution of 2.0 SiOn/NazO weight ratio at a concentration of 4.7 oz. of solid/gal. and a temperature of 200 F. Under these conditions, acleaning time of about 1 /2 seconds was required to clean mineral oil from the sheet to the point where it was free from water break."

It may be indicated that a preferred silicate detergent will include sodium silicate having asilica to soda weight ratio of 1.9 to 2.4 together with a foaming agent such as a polyethylene oxide derivative or saponin. Compositions for the removal of lubricant films of the present invention are more specifically covered in my pending application, Serial Number 487,115 filed March 5, 1943.

While it will ordinarily be preferred to use mineral oil with only the additions above described it will be understood that various other additions and modifications used in the art may be employed without departing from the spirit of the invention. It may for instance be found desirable to include minor amounts of palm oil or other materials such as soluble oils.

While certain illustrative compositions have been described above it will be understood that the ingredients and the proportions may be considerably varied and regulated to produce lubricants of desired character without departing from the spirit of this invention.

I claim:

1. A lubricant for use in the cold roliing of steel comprising a major amount of mineral oil,

from about 0.2 to 0.5 percent sulfonated castor oil, 0.5 to 2.0 percent tricresyl phosphate, and from about 0.05 to 0.3 percent of lorol phosphate.

2. A composition for addition to mineral oil to produce a. lubricant for use in the cold rollinfl of steel comprising substantially 0.2 to 0.5 percent oi sulionated castor oil, substantially 0.5 to 2.0 percent of tricresyl phosphate, and substantially 0.05 to 0.3 percent of lorol phosphate.

3. A composition for addition to mineral oil to produce a high-pressure lubricant suitable for use in the cold rolling of steel, the lubricant being readily removable from steel by use of a silicate detergent, comprising about 20 parts by weight of kerosene, about 15 parts by weight of tricresyl phosphate, about 1.5 parts by weight of lorol phosphate, and about 3 parts by weight of sulionated castor oil.

4. A lubricant for use in the cold-rolling 01. steel comprising a major amount of mineral oil from about 0.2 to 0.5 percent of a sulfonated 011 selected from the group consisting of sulfonated animal and vegetable oils, 0.5 to 2.0 percent tricresyl phosphate, and from about 0.05 to 0.3 percent of lorol phosphate.

5. A composition for addition to mineral oil to produce a lubricant for use in the cold-rollin of steel comprising substantially 0.2 to 0.5 percent of a sulfonated oil selected from the group consisting of suli'onated animal and vegetable oils. substantially 0.5 to 2.0 percent of tricresyl phosphate, and substantially 0.05 to 0.3 percent of lorol phosphate.

RICHARD W. KINGERIEY, Ja.

CERTIFICATE OF CORRECTION Patent No. 2,591, 651.

December 25, 1915.

RICHARD W. RINGERLEY, JR

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 16, for the serial number '*i 37,115" read --l 7 ,115--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of March, A. D. 1914.6.

(Seal) Leslie Frazer First Assistant Comnisslonpr of Patents. 

